exam 3 phy 503 Flashcards
TRUE/FALSE: Patients with a lactase deficiency can digest milk products that contain lactose (milk sugar)?
False: Patients with a lactase deficiency cannot digest milk products that contain milk products (milk sugar). Blood glucose levels do not increase because lactose is not digested to glucose and galactose in these patients.
Duodenocolic Refelx
Reflex begins in the the duodenum and ends in the colon. When the duodenum is distended (stretches), nervous signals are transmitted to the colon which stimulates mass movements.
Enterogastric Reflex
occurs when signals originating in the intestines inhibit gastric motility and gastric secretion.
Intestino-intestinal Reflex
occurs when overdistention or injury to bowel segment signals and the bowel to relax.
Retrosphincteric Reflex
initated when feces enters the rectum and stimulates the urge to defecate.
Vitamin B12
absorbed in the ileum; this absorption requires intrinsic factor which is a glycoprotein secreted by parietal cells in the stomach.
Atrophic Gastritis
a type of autoimmune gastritis that is mainly confined to the acid-secreting corpus mucosa. The gastritis is diffuse and severe atrophy eventually develops. IIeal resection is likely to cause diarrhea but not constipation.
Gastric Ulcer
A stomach ulcer occurs when stomach acid eats through your protective stomach lining, producing an open sore
GERD
caused by gastric acid and bile reflex into the esophagus, musocsal damage and epithelial cell transformation lead to Barret esophagus.
What is the highest concentration in saliva under basal conditions?
Bicarbonate
The presence of fat, carbohydrates, or protein in the duodenum stimulates the release of which hormone from the duodenal mucosa?
GLIP: Glucose-dependent insulin-tropic peptide
GLIP is the only gastrointestinal hormone released by all 3 major foodstuff (fats, proteins, and carbohydrates).
TRUE/FALSE: GLIP is a strong stimulator of insulin release and is responsible for the observation that an oral glucose load releases more insulin and is metabolized more rapidly than equal amount of glucose administrated intravenously.
True
TRUE/FALSE: CCK AND VIP stimulates the release of insulin?
False: Neither CCK or VIP stimulate the release of insulin.
Digestion of which of the following is impaired to the greatest extent in patients with achlorhydria?
A) Carbohydrates
B) Fat
C) Protein
C: Protein
Achlorhydria means that the stomach fails to secrete HCL (hydrochloric acid). This condition is diagnosed when the pH of the gastric secretions fails to decrease below 4 after stimulation by pentagastrin. When acid is not secreted, pepsin also isn’t secreted. Because pepsin requires an acid medium for activity, protein digestion is impaired.
Achalasia
a condition in in which LES (lower esophageal sphincter) fails to relax during swallowing. As a result, food swallowed into the esophagus fails to pass from the esophagus into the stomach. Indication on a chart will show a high pressure that fails to decrease after swallowing.
The proenzyme pepsinogen is secreted mainly from ?
Gastric Glands of the stomach
-Pepsinogen is the precursor of the enzyme pepsin. Pepsin is secreted from the peptic or Cheif cells) of the gastric gland.
What hormone released by the presence of fat and protein in the small intestine and has a major effect in decreasing gastric emptying is called?
CCK
-its the only gastrointestinal hormone that inhibits gastric emptying under physiological conditions.
Compared with the plasma, saliva has the highest relative concentration of which ion under basal conditions?
Potassium
TRUE/FALSE: Sodium and Chloride ions have low concentrations under basal conditions?
TRUE
Which of the following can inhibit gastric acid secretion?
A) Somatostatin
B) Secretin
C) GLIP
D) Enterogastrones
E) Nervous Reflexes
(F) All the above
F) all the above
Somatostatin, Secretin, GLIP, Enterogastrones, Nervous Reflexes
The gastrointestinal hormones have physiological effects that can e elicited at normal concentrations, as well as pharmacological effects that require higher than normal concentrations. What is the direct physiological effect of the various hormones on gastric acid secretion?
Gastrin: Stimulate
Secretin: Inhibit
CCK: No effect
GLIP: Inhibit
Motilin: No effect
The cephalic phase of gastric secretion accounts for about 30 percent of the acid response to a meal. Which of the following can completely eliminate the cephalic phase of gastric secretion?
A) Antacids (rolaids)
B) Antigastrin Antibody
C) Atropine
D)Histamine H2 blocker
E) Vagotomy
F) Sympathectomy
E) Vagotomy
Because the cephalic phase of gastric secretion is mediated entirely by way of the vagus nerve, vagotomy can abolish the response.
TRUE/FLASE: Antacids neutralize gastric acid and inhibit gastric secretion?
False
Antacids neutralize gastric acid but DO NOT inhibit gastric secretion.
Migrating motility complexes (MMCs) occur every 90 minutes between meals and are thought to be stimulated by the gastrointestinal hormone motilin. An absence of MMCs causes an increase in?
Intestinal Bacterial
-MMCs are peristaltic waves of concentration that begin the stomach and slowly migrate in an aboral direction along the entire small intestine to the colon. By sweeping undigested food residue from the stomach, through the small intestine and into the Colon, MMCs function to maintain low bacterial counts in upper intestine. bacterial overgrowth syndrome can occur when the normally low bacterial colonization in the upper GI tract increases significantly.
Gastric empyting is tightly regulated to ensure that chyme enters the duodenum at an appropriate rate. What event promotes gastric emptying under normal physiological conditions in a healthy person?
Tone of Orad Stomach: increases
Segmentation contractions in small intestine: Decreases
Tone of pyloric sphincter: Decreases
Gastric emptying is accomplished by coordinated activities of the stomach, pylorus, and small intestine. Conditions that favor gastric emptying include (a) increased tone of the orad stomach, which helps to push chyme toward the pylorus.
toxin from V.cholerae
The toxin from V. cholerae (cholera toxin) causes an irreversible increase in cAMP levels in the enterocytes located in the crypts of Lieberkühn of the small intestine. This increase in cAMP causes an irreversible opening of chloride channels on the luminal membrane.
True/False: Movement of chloride ions into the gut lumen causes a secondary movement of sodium ions to maintain electrical neutrality?
True
The gastrointestinal hormones have physiological effects that can be elicited at normal concentrations as well as pharmacological effects that require higher than normal concentrations. What is the physiological effect of the various hormones on gastric emptying?
Gastrin: none
Secretin: None
CCK: Decrease
GLIP: None
Motilin: None
CCK is the only gastrointestinal hormone that inhibits gastric emptying under normal physiological conditions. CCK inhibits gastric emptying by relaxing the orad stomach, which increases its compliance.
The function of the gastrointestinal (GI) tract can be summarized by the following mechanism(s):
(A) Motility
(B) Secretion
(C) Digestion
(D) Absorption
(E) All of the above
E: All the above
Which one of the following is consistent with absorption of glucose molecules across the intestinal epithelium?
(A) Glucose enters the intestinal epithelial cell through glucose channels in the apical membrane and leaves the cell through the basal membrane by facilitated diffusion.
(B) Glucose enters through the apical membrane by facilitated diffusion and leaves through the basal membrane by facilitated diffusion also.
(C) Glucose enters the cell through the apical membrane by co-transport with Na+ and leaves the cell through the basal membrane by facilitated diffusion.
(D) Glucose enters the cell through the apical membrane by facilitated diffusion and leaves the cell through the basal membrane by co-transport with Na+.
(E) None of the above.
C): Glucose enters the cell through the apical membrane by co-transport with Na+ and leaves the cell through the basal membrane by facilitated diffusion.
Most of the chemical digestion in the gastrointestinal (GI) tract occurs in the:
(A) Mouth
(B) Stomach
(C) Small intestine
(D) Large intestine
C): Small Intestine
Most of the water and electrolytes absorbed across the walls of the gastrointestinal (GI) tract is absorbed in this region:
(A) Mouth
(B) Stomach
(C) Small intestine
(D) Large intestine
C): Small intestine
